March 2026

Our March meeting was attended by a group of 22 members to hear our guest speaker, Glenn Turner, a retired master mariner. He discussed waves in the ocean, what you might see when on the sea or on a beach and how to understand what you are observing.

Glenn explained that waves in water are caused by the wind blowing over the surface. Wind waves range in size from small ripples to waves over 30 metres high, being influenced by wind speed, duration, fetch (area affected) and the depth of the water. The stronger the wind, the higher and more powerful are the waves. Although there are complex mathematical equations to explain wave formation, fortunately, Glenn did not go into detail! Instead, he explained wave formation with analogies involving types of chocolate bar, which featured throughout the talk and were very relatable.

Surprisingly, when a wave is moving forwards, the water underneath does not travel in the same direction, instead moving up and down. This was illustrated by looking at the ‘Mexican Wave’ at sporting events where the wave moves along but spectators are moving up and down in their seats.

Glenn described the formation of many wave types, including surf waves, tsunamis, tidal bores, rip currents and ‘rogue’ waves. He demonstrated the power of these waves with diagrams and videos.